Diodes may be utilized in integrated circuitry for numerous applications. For instance, diodes may be utilized for regulating current flow, and/or may be utilized as select devices for selectively accessing components of the integrated circuitry.
A class of diodes that is of particular interest are so called metal-insulator-metal (MIM) diodes, which are diodes having one or more electrically insulative materials sandwiched between a pair of electrically conductive electrodes. The electrodes may be defined to be a first electrode and a second electrode. The diodes may be considered to enable electron flow from the first electrode to the second electrode, and to impede electron flow from the second electrode to the first electrode. Since current flow is defined to be in the opposite direction to electron flow; the diodes may also be considered to enable current flow from the second electrode to the first electrode, and to impede current flow from the first electrode to the second electrode.
A portion of the electrically insulative material between the diodes will be directly against the first electrode. It is desired that the electrically insulative material directly against the first electrode by highly homogenous, and be of high purity, to obtain high reproducibility of diode characteristics from one diode to another. It is proving difficult to form the electrically insulative material to the desired homogeneity and purity with conventional methods using low temperature processes (i.e., processes at less than 450° C.). For instance, the electrically insulative material may be conventionally formed by atomic layer deposition (ALD) of an oxide. The ALD-formed oxide may contain contaminating carbon or other components of precursors utilized in the ALD. The contaminating substances may interfere with performance of diodes having such oxide incorporated therein.
It is desired to develop new methods for forming electrically insulative material of MIM diodes. It is also desired to develop new diode structures having highly homogenous electrically insulative material directly against the first electrode.